William Wellesley was the second son of Garrett Wesley, 1st Earl of Mornington, from whom he inherited the title after the death of his elder brother Richard, Marquess Wellesley and 2nd Earl of Mornington, in 1842. In 1781 he took the additional surname of Pole, having succeeded to the estates of his cousin William Pole of Ballyfin (see lot 27), and in 1821 he was created Baron Maryborough. Like all his brothers he was politically active, though it was his younger brother Arthur (1769-1852), the 1st Duke of Wellington, whose views he shared most and his career was very much a product of the latter's illustrious presence.
The picture depicts William at the age of fourteen, the year after he left Eton, having been there only for two years. It is not quite clear as to why he is depicted pointing with his left hand to the globe, notably to New York and holding a partially rolled up map inscribed 'The Provinces of New York and New Jersey'. Neither he nor any member of his family is known to have had a particular connection with these places. It is, however, probably not mere coincidence that in 1776 and 1777 the British military forces were mainly active in this area of North America, the year the painting is dated. The map and globe may even allude to his forthcoming commission in the Navy, which he joined in 1778, and the family's expectation that he would soon be sent to America.